Portland cement clinker quenching process



Sept. 20 1938. H. E. KAISER PORTLAND CEMENT CLINKER QUENCHING PROCESSFiled septl 20, 1937 In vento/1 l1 any E. Kai; er:

Harney.

Patented Sept. 20, 1938 UNITED s'rlircs` PArENT OFFICE This inventionhas vide 'en improved process POBTLAN CEMENT PRO Harry fornia. Calif.,

oLrNnEn QUnNcnlN cess E. Kaiser, Colton. Calif., assignor to Cali-Portlnnd Cement Company, a corporation o! California Los AAngeles,

Application September 2t, 1937, ySerial No. 164,687

16 Claims.

for its general objectto profor quenching Portland is distinguished inone refrom prior clinker quenchthe quenching medium comn prises agroundPortland cement row mixture.

A Portland cement raw mixture may be donned es comprising u mixture ofargillaceous end ce1- ccreous materiels which when peretures ofincipient fusion will result in the formation of Portland cementclinlrer cs hnown by accepted stcndcrds.

Since the chemical com-` position oi the Portland cement row mixture haso. direct -becringj upon the eectiveness of the mixture es o medium forquenchi the Portland cement clinlrer, row

mixtures which l propose to employ in the present process may further bedehnen with respect containing' 12.0% equivalent, ond 70% (CeCOs) orequivalent,

to chemical composition es t0 26.0% silica (Sim), Or

to 85% culcium carbonate plusthe usuel percent.c

eues oi other normal ingredients ci Portland cement ruw mixtures.

lConsidering the row mixture specidcolly fiom the stendpoint of c.

ciuni curbonute content is imp quenchine,r medium, its culortont with'.eii'er1 ence tothe heet absorbing capacity of the mu! mixture. undtherefore materiel. Since it uorily e. porti cludes other footers itselcacy es o. quenching is contemploted that ordion of the ruw mixturewill become heeted by the clinher to o tempereturc of heet required toconse of cor-bon dionid enters the totnlheot absorbing capacity oreffective speclilc heut oi the row mixture.

in the quenching operation incipient colcinction, the` the endcthecliloerution into e, considerction oi term inend, while variable in eccordonce with e; predetermined degree oi celcino.- tion, muy be dened osthe ernount of heet required to dehydrnte the mixture, reise itstemperoture to the point at which incipient calciumtion will stort,desired degree. in usine e Portland quenching medium und continuecolcinetion to the.

One advantage, among others,v

cement row mixture es the lies in the fact thut its colciurn corbonetecontent is sumcicntly hiuh to permit culclnotion to on extent that ineffect will give vthe materiel a, higher heet absorbing capacity thun itwould otherwise lieve in the absence of c f content.

compnreble lime Celcinetion is pro- 'znoted by reoson of the presence ofo, large numf ber of calcium carbonate particles in contact with thehot'clinlrer.

In the more recent nite advantages have been reco development of thesrt, defignized to result culcined to tem- (ci. ecs-'53) Y fromquenching, i. e. very rapid cooling, of Portland cement clinker. Byquenching the clinker immediately or very shortly after itpasses fromthe clinkering zone of the kiln, there is a tendency to freeze theequilibrium which has been set up ut1 the clinkering temperatures amongthe various compounds in the clinker. It will be unnecessary to enterinto a. specific discussion of the individuel compounds or theirinterreletionship and eects under equilibrium conditions; sufllce tostate that it has become generally recognized that by maintaining orfreezing thnt equilibrium by rapid quenching, certain propertiesbf theclinker itself', and of the ilnished cement, ore definitely improved.

All the possible edects und advantages of rapid uucnchlne lieve not ssyet become definitely estoblished. However, there are clesr indicationsoi lieneilclel results in c. number of respects, 'and here l refer toapparent advantages determined from observations und tests of Portlandcement clinher that hes been quenched by sudden und intimate edmixturewith finely ground Portland cement ruw mixture. Quenching appears topromote euse oi grindebility, as indicated by the fact that the quenchedclinker will be reduced to e.

suhstentiolly iiner state of division when subjected to o given grindingoperation, then s. normelly cooled or unquenched clinlrer.y It is alsoindicated that the resultant clinker will have less tendency to dustthsnnormolly. Further tests indicate thet cementitious or concretemixtures mede with cement from the quenched olinher, show n materiallylower degree of expansion under the Stenders tests; n is aus@ believedniet beneficial eiects ere had upon the properties of the clnher bysubjecting the @linker to quenching und permitting it to cool Within thequenching temperature renee in en atmosphere of carbon dionld, esis-mede possible by the invention by t0 virtue of the cnlcium carbonatecontent of the row mixture.

" In 'accordance with the` invention,` the hot clinher is :red withnelyground Portlend cement ruw mixture, preiemhly. ediotely 4J after theclinker leaves the clinlrering zone oi the kiln. in order that theireezing" edect of quenching muy be hed upon the clinher while it isstill. cs close os possible to the clinhering tempereture of the kiln.Any suitable quantity or proportion 'of relatively cold raw mixture maybe edmixed with the clinker that will produce the desired and properquenching effect. Also. the raw mixture muy be cold, or it may be mildlyheated, solongas ample temperature diilerential exists between theclinker" and raw mix in accordance with the proportionsused. Where theprocess is continuous, as it usually will be,

I will ordinarily introduce the ground raw mixture to the hot clinker ata rate such that the potential Portland cement quantity of the rawmixture will at leastV correspond substantially to thequantity ofclinker admixed therewith. (By

l potential Portland cement quantity of raw mixture, I mean the.quantity of Portland cement clinker that a given amount of the rawmixture will produce upon calcination at Portland cement any suitablemanner, for example in an elongated cylinder that is rotated to givecontinuous mixing agitation. With the further view of enhancing rapidquenching by promoting intimacy of contact between the raw mix andclinker particles, the raw mixture preliminarily is rather finelyground, for example to a particle sizel such that substantially all willpass a fty mesh screen, and 70%' to 100% will pass a two hundred meshscreen.

The admixture of clinker and raw mix is maintained in a cooling zone fora period of time' required to drop the clinker temperature'through theproperA quenching range. Various factors may enter into the timeelement, but it may be stated, as illustrative, that ordinarily it willbe desirable to cool the clinker from a temperature that may rangebetween 1800 to Z600 F., to a temperature under 1000" F. within a periodof l be such that` the heat of the clinker will produce some-incipientcalcination of the raw mixture.

This will result in a liberation of carbon dioxid clinker from adheringraw mixture particles.

The clinker then may be ground or processed by any of the usual methodsof producing Portland cement, and the separated raw mixture may' be usedin any desired manner. For example,

after furthercooling, all or a portion of the sepav rated raw mixturemay again be used as a quenching medium, or the raw mixture, preferablywhile in a heated condition, maybe caT- cined to produce Portland cementclinker in the .same kiln in which the quenched clinker has been formed,or in diierent kilns. Such subsequent disposition of the separated rawmix for use inmaking Portland cement clinker, more particularly isincluded in the subject matter of my copending application, Ser. No.164,686, led

September 20, 1937, for Process of manufacturing Portland cement.

The foregoing description of the invention may perhaps be amplied toadvantage by reference to `the accompanying drawing which shows, in

-r flow sheet form, a typical and illustrative system for carrying outthe process. f.

Portland cement clinker formed in the clinker- -inlet end lita of thecooling chamber.

` within the cooler'.

- clinker at the inlet lend of chute Il and directly after the clinkerleaves the kiln, or the raw mixture may be taken via line l5 and fedinto the As illustrated, the feed end of the chamber may contain asuitable refractory lining it. The clinker and raw mixture are rapidlybrought into intimate contact and subjected to thorough admixture withinthe rotating cooler l2. The admixture lwill remain in the cooler for aperiod of time required to quench the clinker through the propertemperature range, and as observed in the foregoing, during this timethe raw mixture preferably will undergo some incipient calcinationresulting in the liberation of carbon dioxid At the discharge end lflbof the cooler,the material passes over a perforated or screen section ilof the cooler shell. at which point the raw mixture particles, beingsmaller than the pieces of clinker, pass through the screen into ahopper I8 from which the .ma-z

terial is conveyed through line i9 to storage bin 20. For the purpose offurther cooling the clinker to a temperature suitable for handling orstorage, and in order to subject the clinker to any further agitationnecessary to remove adhering particles of raw mixture, the yclinkerleaving cooler I2 may be conveyed through line 2l to a second rotatingcooler 22. This cooler may also have one or more screen sections 23through which the freed raw mixture particles will pass into hopper 2lito be conveyed via line 25 `to the storage bin 20. The clean clinkerfinally is discharged at 2t into the clinker storage bin 2li.

If for any reason it may be found advantageous to do so. cooled rawmixture may be returned from bin 20 to be used in the clinker quenchingoperation. Ordinarily, it will bev preferred to But, as indicated above,that voperation is more 2. The process thatv includes, rapidly quench"`ing finished lhot- Portland cement clinker by intimately admixing withthe clinker a nely ground substantially dry Portland cement raw mixture.

3. The process that includes, rapidlyquenching iinished hot PortlandAcement clinker by' intimately admixing with the clinker a. heated .andlnely ground substantially dry Portland cement raw mixture.

4. The process that includes, rapidly quench-` ing ilnished hot Portlandcement clinker by admixing with the clinker a Portland cement rawmixture at a `rate such that the potential Portland cement quantityofthe raw mixture corresponds substantially to Ithe quantity of clinkeradmixed therewith. f

5. 'I'heprocess thatincludes, rapidly quenching a continuously iiowingstream of ilnished hot .araches L Portland'mei clinker byv continuouslyintroducing to and intimately admixing with the 'clinker a suhstantiallydry Portland cement raw mixture. il

6. The process thatinclude's, rapidly quenching a continuous ilowingstream of finished Portland cement clinker flowing from a kiln,.bycontinuously introducing to and rapidly admixing with the clinkerimmediately after its removal from the kiln, a substantially dryPortland cement raw mixture' and thereby rapidly cooling the clinker toa temperature belowsubstantially 1100 F. 'f L 7. Theprocess matelyadmixing lwith the clinker a Portland cement raw mixture, and therebydehydratingand artially calcining the raw mixture. l

8. The process that includes,-frapid1y quench- .ing a continuouslyflowing stream ot finished hot Portland cement clinker by continuouslyintroducing to and intimately-admixing with the clinker a` Portlandcement raw mixture, and

, thereby rapidly cooling the clinker and dehydrating and partiallycalcining the raw-mixture.

9L The process thatincludes, rapidly quenching inishedhot Portlandcemnteclinker by'intimately admixin'g with the clinker a finely groundPortlandcement raw mixture, 4and thereafter separating the raw mixturefrom the clinkr.

10. YThe process that includes, rapidly quenching a continuously owingstream of iinished hot Portland cement clinker lby continuouslyintroduclng to and intinately aumixing with the ciinkera substantiallydry Portland cement raw mixture, and thereafter continuously separatingx the raw mixturefrom' the clinker'.

i 11. The process that includes, rapidly quenching nlshed hot Portlandcement cllnker by intimately admixing with the clinker a Portlandcement` raw mixture and maintaining the admixture in an latmospherecontaining' carbon dioxid -released from the raw mixture.

thatincludes, rapidlyquenching iinished hot Portland cement clinker byintiall the clinker* by adxnxng with the clinker a4 mixture oicalcareous and argillaous materials, and then separating said mixturefro the quenched clinker.

14. The process'that inc1udes,-discharginga stream of nished'hotPortland cement clinker from a clinkerlng acne, andthenrapidly-quenching Vall the clinker by immediately admixing with theclinker a mixture of calcareous and argillaceous materials in a coolingzone, subjecting the admixture to agitation in said cooling zone, and

then separating said mixture from the quenched clinker.

15, The process that includes, continuously passing a stream of finishedhot Portland cev ment clinker from a clinkering zone, then rapidlyquenching the clinker by continuously introducing to and intimatelyadmixing with leaves the clinkering zone, a nely ground Portlandcementraw mixture, and passing the 'admixture through a cooling zone.

16. The process that "includes, continuously :the hotclix'lker streamimmediately after it passing a stream of finished hot Portland ce-l-ment clinker from a clinkering zone, then rapidly quenching the clinkerby continuously introducingl to and intimately admixing with the hotlclinker stream immediately ,after it leaves the cllnkexing zone, aiinely ground Portland cement raw mixture, passing the admixture througha cooling zone, and then separating the raw mixture from the clinker. Y

HARRY E. msm

